Float-distributor for direct chill casting

ABSTRACT

A float-distributor for direct chill casting of metals, particularly, aluminum and aluminum base alloys. The floatdistributor comprises a float adapted to float on the surface of the molten metal in the mold. The float is adapted to fit about a feed nozzle which supplies the molten metal to the mold. Means for distributing the molten metal about the periphery of the mold is provided and is supported beneath the float. The distributing means generally comprises a cone shaped distributor which is supported in axial alignment with the feed nozzle. The apex angle of the distributor is generally kept between about 60* and 150*. The float may include means for increasing its buoyancy as the flow rate of molten metal issuing from the feed nozzle increases. The float may also contain means for preventing capillary flow of molten metal between the float and the feed nozzle.

United States Patent 1191 Sevier 1 51 Aug. 14, 1973 FLOAT-DISTRIBUTORFOR DIRECT CHILL [73] Assignee: Olin Corporation, New Haven,

Conn.

[22] Filed: Aug. 13, 1971 [21] Appl. No.: 171,462

[52] US. Cl. 164/281, 137/432 3,349,838 10/1967 Baier PrimaryExaminer-Robert D. Baldwin Attorney-Robert l-l. Bachman et a1.

[5 7] ABSTRACT A float-distributor for direct chill casting of metals,particularly, aluminum and aluminum base alloys. The float-distributorcomprises a float adapted to float on the surface of the molten metal inthe mold. The float is adapted to fit about a feed nozzle which suppliesthe molten metal to the mold. Means for distributing the molten metalabout the periphery of the mold is provided and is supported beneath thefloat. The distributing means generally comprises a cone shapeddistributor which is supported in axial alignment with the feed nozzle.The apex angle of the distributor is generally kept between about 60 and150. The float may include means for increasing its buoyancy as the flowrate of molten metal issuing from the feed nozzle increases. The floatmay also contain means for preventing capillary flow of molten metalbetween the float and the feed nozzle.

32 Claims, 4 Drawing Figures Patented Aug. 14, 1973 3,752,217

5 Sheets-Sheet l INVENTOR: PETER E. SEWER ATTORNEY Patented Aug. 14,1973 5 Sheets-Sheet 3 PETER E. SEWER INVENTOR ATTORNEY FLOAT-DISTRIBUTORFOR DIRECT CHILL CASTING BACKGROUND OF THE INVENTION This inventionrelates to an improved floatdistributor for the direct chill casting ofmetals, particularly, aluminum or aluminum based alloys. Improved caststructure and surface appearance is obtained for direct chill castingots, particularly, extrusion ingots, together with increased castingspeed, by the use of a float-distributor that has a conical distributionelement and a low metacentric height. The float-distributor also actssimultaneously as a flow control valve.

In the direct chill casting process, the difficulty in obtaining auniform distribution of molten metal about the periphery of acylindrical extrusion ingot mold is well known. Uniform distribution isessential if inhomogeneities in ingot structure leading to poor metalfinishing performance in the subsequent extrusion are to be avoided. Itis important that the structure of the extrusion ingot be substantiallyfree from transverse and longitudinal inhomogeneities.

Transverse inhomogeneities are most often caused by using afloat-distributor which has a number of radially disposed dischargeports; the jet of hot metal leaving each port causes structuraldifferences in the ingot yielding a flower petal pattern structureformed by a mixture of coarse and fine dentritic elements.

US. Pat. Nos. 3,289,291, granted June 23, 1969 and U.S. Pat. No.3,050,792, granted Aug. 28, 1962 illustrate typical prior art designswhich are subject to such transverse inhomogeneities.

Longitudinal inhomogeneities are caused by phenomena in the air gapbetween the mold wall and the ingot surface where it has shrunk awayfrom the mold wall. This defect is commonly known as the Altenpohl bandand can be minimized by keeping a small head of metal within the mold.

Direct chill casting with a small head of metal in the mold is generallymore difficult than casting with a large head of metal. It demandsaccurate alignment of the central feed nozzle and its associatedfloatdistributor which controls both the level of metalin the mold andits distribution.

Float-distributors with a flat control surface as in that the apex angleof the cone must be limited within specific ranges in order to obtainthe desired distribution of metal within the mold. The more acute theapex angle, the greater is the tendency of the molten metal to be drivendown into the cast ingot and, thereby, form a deeper crater. Theformation of a deep crater makes the ingot subject to cracking or hottearing and is particularly deleterious when casting stress sensitivealu-. minum alloy because it increases the thermal stresses which occurin the cast ingot.

SUMMARY OF THE INVENTION In accordance with this invention, an improvedcone shaped float-distributor has been developed which simultaneouslyproduces a substantially uniform lateral distribution of molten metal tothe casting, coupled with a fine degree of level control within themold. The float-distributor of this invention also provides increasedstability of operation at high casting speeds because it has arelatively low metacentric height.

The float-distributor of this invention comprises a novel float meanswhich is adapted to maintain accurate alignment between a conicaldistributor element and a feed nozzle. The float further includes meansfor preventing molten metal from flowing by capillary action between thefloat and the feed nozzle and means for increasing the bouyancy of thefloat as molten metal flow rates increase in order to provide improvedvalving action by the distributor element and to shut off the flow ofmetal from the feed nozzle at high flow rates.

The distributor element of the float-distributor of this invention has aconical shape with the top portion of the cone being rounded off into aspherical surface to increase the tolerance of the distributor tovertical misalignment between the feed nozzle and the distributor. Thecone shaped distributor is generally formed of a material having adensity greater than or equal to that of aluminum and, preferably, adensity at least twice as great as that of aluminum.

The support arms which connect the float to the distributor cone arekept as small as possible so that a substantially uniform distributionof metal is provided US. Pat. No. 3,050,792 are often used and the metalin the mold flows radially outward. The multiple discharge ports in thebottom of the float-distributor cause unequal metal distribution in thehorizontal plane resulting in the flower petal defect discussed above.

Further, such distributors of the type shown in the patent tend to floatwith only a small part of their total volume submerged because they havea high metacentric height and as the casting speed of the ingot isincreased, the distributor tends to discharge more metal from the portsof one side than from the remaining ports, and thus, tilts with respectto the feed nozzle. This tilting problem is self-propagating since thereis no effective restoring couple and the tilt is usually only limitedwhen the feed nozzle interferes with the hole in the distributor. Thistilting probelm exaggerates the unequal distribution of metal throughthe discharge ports and, consequently, further deteriorates themicrostructure of the resulting ingot.

Cone shaped distributors have been employed in U.S. Pat. No. 2,891,291and French Pat. No. 1,385,585; however, it has not been recognized inthese patents about the 360 periphery of the mold. Preferably, thedistributor element and support arms are an integral one piece castingwhich is readily assembled to the float by means of Pal nuts orTinnerman speed nuts.

Accordingly, it is a principal object of this invention to provide afloat-distributor for direct chill casting of molten metals,particularly, aluminum or aluminum based alloys having improveduniformity of distribution of molten metal about the periphery of themold.

It is another object of this invention to provide a float-distributor asabove, wherein the distributor ele ment has a conical shape.

It is a further object of this invention to provide a float-distributoras above, wherein the float includes means for preventing flow of moltenmetal between the float and the feed nozzle by capillary action.

It is a still further object of this invention to provide afloat-distributor as above, wherein the float includes means forincreasing its bouyancy as molten metal flow BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1 is-a partial cross sectional view of a typicalfloat-distributor assembly in accordance with this invention.

FIG. 2 is a perspective view of a typical conical distributor element inaccordance with this invention.

FIG. 3 is a cross sectional view of a typical floatdistributor assemblyin accordance with this invention in place in a direct chill castingapparatus prior to the beginning of casting.

FIG. 4 is a cross sectional view of a float-distributor assembly inaccordance with this invention in place in a direct chill castingapparatus during casting.

I DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to thedrawings an especially to FIG. 1, there is shown a partial cross sectionof a floatdistributor l in accordance with this invention. Thefloat-distributor 1 comprises a float 2, a distributor ele' ment 3 andmeans 4 connected to the float 2 for supporting the distributor element3.

The float 2 is of a highly novel design and is adapted to have a feednozzle 5 protrude through it. The float 2 comprises a bottom portion 6which contacts the molten metal in the direct chill casting mold, a topportion 7 and a peripheral wall 8. The peripheral wall 8 may have anydesired shape but is preferably shaped to conform to the insideperiphery of the mold and for most applications, therefore, it has acylindrical shape.

The float 2 has a hole 9 passing substantially centrally through itextending from the top portion 7 to the bottom portion 6. The hole 9comprises at least two portions. The first portion 10 has a diametersubstantially greater than the feed nozzle 5 and provides means forpreventing flow of molten metal between the float 2 and the feed nozzle5 by capillary action.

The second portion 11 of the hole 9 has an inside diameter which is justslightly greater than the outside diameter of the feed nozzle 5. Thesecond portion 11 of the hole 9 provides means for maintaining thecentering of the distributor element 3 below the feed nozzle 5.Preferably, the inside diameter of the second portion 11 is from about0.050 to 0.200 inch larger than the outside diameter of the feed nozzle5, and still more preferably, the diameter of the second portion 11 isfrom about 0.100 to 0.150 inch larger than the outside diameter of thefeed nozzle 5.

For aluminum and aluminum based alloys, the inside diameter of the firstportion 10 of the hole 9 may be set as desired but must be large enoughin relation to the outside diameter of the feed nozzle 5 to preventcapillary flow of molten aluminum or aluminum base alloy between thefloat 2 and the feed nozzle 5. It has been found that preferably theinside diameter of the first portion 10 is at least about three-eighthsinch greater than the outside diameter of the feed nozzle 5 and, morepreferably, it is at least about one-half inch greater than the outsidediameter of the feed nozzle 5.

If the hole 9 had an inside diameter equal to the inside diameter of thesecond portion 11 throughout its whole length, molten metal might flowby capillary action along the annular gap between the feed nozzle 5 andthe hole 9 and would be subject to freezing, thereby immobilizing thefloat-distributor 1. Therefore, an enlarged hole portion 10 is providedto prevent capillary flow of molten metal between the feed nozzle 5 andthe float 2. The shoulder 12 at the juncture of the hole portions 10 and11 may have any desired shape such as a flat as in FIG. I or a radius asin FIGS. 3 and 4.

The float 2 preferably also includes means 13 for increasing itsbouyancy as the flow of molten metal issuing from the feed nozzle 5increases. This means 13 preferably comprises an inclined portionextending outwardly between the bottom 6 and the wall 8 of the float 2.Where the float 2 has a cylindrical shape, namely, a cylindrical wall 8,the inclined portion 13 will have a conical shape. The inclined portion13 may extend over the full thickness of the float 2 between the top 7and bottom 6 portions, thereby, eliminating the wall 8 or any portion ofthis thickness.

In operation, the float 2 is only partially submerged in the moltenmetal and only a small portion of the inclined surface 13 is submerged.At high rates of molten metal flow from the feed nozle 5, the float 2tends to be submerged to a greater extent in the molten metal by virtueof the interaction between the flowing molten metal and the distributorelement 3. Therefore, a greater portion of the inclined surface 13 ofthe float 2 is submerged providing increased displacement and,therefore, increased bouyancy. The inclined surface 13, therefore,provides a novel means for increasing the bouyancy of the float 2 tocombat the tendency of the float '2 to submerge under the influence ofhigh holten metal delivery rates issuing from the feed nozzle 5.

For a cylindrical float 2, it has been found that the outside diameterof the float as compared to the inside diameter of the casting moldshould preferably be within the limits expressed by the followingrelationship. The outside diameter of the float 2 should be from about0.86 X I.D. inch (inside diameter of the mold) 0.81 inch to about 0.98 XI.D. inch 0.82 inch. It has been found that floats 2 having an outsidediameter falling within the range delineated by the above relationshiphave markedly improved stability in the horizontal plane over a widerange of metal flow rates issuing from the feed nozzle 5.

It should also be noted that the float 2 is relatively thin as comparedto its diameter having a diameter to thickness ratio preferably greaterthan 3 to l and, more preferably, greater than 5 to l.

The second major element of the float-distributor l is the distributorelement 3 which in accordance with this invention preferably has aconical shape. The cone D has an apex angle a which varies from about 60to about l50 and, preferably, from about to By varying the apex angle a,metal distribution patterns can be obtained ranging from a substantiallyhorizontal disc type pattern to a cone type pattern. As aforenoted, themore acute the apex angle a, the greater is the tendency of thedistribution pattern to drive the molten metal deeper into the casting,thereby, forming adeep cavity with the attendant problems resultingtherefrom. Therefore, the 60 minimum apex angle has been chosen as thepractical minimum for substantially eliminating the problems associatedwith distribution cones having highly acute apex angles.

An apex angle a of at least 90 is preferred because the distributionpattern resulting therefrom delivers the molten metal closer to theliquid-solid interface of the ingot as it is being cast.

It has been found that the diameter of the base 14 of the cone shapeddistributor D should preferably be sized with reference to the bore 15diameter of the feed nozzle 5. Preferably, the ratio of the cone base 14diameter to the feed nozzle bore diameter is from about 1.6 to l to 2 tol.

The depth of the apex 16 of the cone D below the bottom 6 of the float 2is determined by practice and is dependent to some extent upon thediameter of the casting, the alloy being cast and other castingconditions.

The apex 16 of the cone D is substantially centered about thelongitudinal axis of the feed nozzle 5. Greater than usual tolerance tovertical misalignment between the longitudinal axis of the feed nozzle 5and the cone axis of the cone D is provided by rounding off the apex 16of the cone D into a substantial spherical surface. Therefore, thedistributor element 3 of this invention preferably has a first portion17 having a conical surface and a second apex portion 16 having asubstantially spherical shape. This configuration allows formisalignment between the axes of the cone D and the feed nozzle 5 of asmuch as 2 to 3 without interfering with the ability of the distributorelement 3 to regulate or shut off metal flow from the feed nozzle duringcast- The cone shaped distributor D is supported by the float 2 byconnecting means 4 which preferably comprises arms 18 connected to thecone D and which pass through the holes 19 in the float 2 and aresecured by nuts 20 to the float.

The connecting arms 18 are made as narrow or as small in diameter aspossible so that a substantially uniform distribution of molten metal isobtained about the 360 periphery of the mold. it has been found mosteconomical in accordance with this invention to form the connectingmeans 4 and distributor element 3 integrally as a casting as shown inFIG. 2. This is not meant to be limitive of the invention, however, andthe connecting means 4 and distributor element 3 need not be integrallyformed but may be separate pieces secured together by conventionaltechniques.

In the preferred assembly, however, an integral casting is employed withthe connecting means 4 comprising the narrow arms 18 which protrudethrough the holes 19 in the float 2. Flanges 21 are provided on the arms18 for locating the depth of the cone apex 16 below the float 2. Theseflanges 21 may be integrally cast with the connecting arms 18 anddistributor element 3 or may be adjustable as, for example, theconnecting arms 18 could be threaded and the flanges 21 could comprisesimple nuts.

It has been found in accordance with this invention, however, that it ismore economical and preferable to leave the connecting arms 18unthreaded and employ in place of threaded nuts, Pal" nuts and Tinnermanspeed nuts as are well known in the art. These nuts may be screwed orpushed onto the unthreaded arms 18 to lock them in place in a mannersimilar to standard threaded nuts on threaded arms.

As shown in FIG. 1, the connecting arms 18 protrude a substantialdistance above the top surface 7 of the float 2. The reason for thiswhich will become more apparent with reference to FIG. 3 is to providemeans for retaining the float-distributor assembly 1 in position priorto casting.

The float-distributor assembly 1 of this invention has a fairly lowmetacentric height as compared to floatdistributors previously employed.The low metacentric height of the float-distributor l is obtainedbecause the distributor element 3 preferably has a density greater thanor equal to aluminum and more preferably greater than twice that ofaluminum and is suspended below the float within the molten metal. It,therefore, acts similar to the keel of a sail boat providing improvedstability over a wide range of metal flow rates issuing from the feednozzle.

The float 2 is preferably formed of a heat resisting material such asMarinite though it may be formed of other materials such as oxidizedstainless steel; however, Marinite is the preferred material inaccordance with this invention. When formed of a metal such as stainlesssteel, the float should be hollow to provide adequate bouyancy. Thefloat 2, then, must be formed of a heat resisting material which willnot contaminate the metal being cast or it may be coated so as to avoidcontamination, and must be sufficiently bouyant to float substantiallyon the surface of the molten metal.

The distributor element 3 is preferably formed of heat resistant castiron. However, it may be formed of other materisl as aforenoted having adensity greater than or equal to that of molten metal being cast. Theuse of cast iron is preferred, however, since it provides a very lowmetacentric height for the float-distributor of this invention and,thereby, the markedly improved stability as aforenoted.

Generally, when a cone D formed of a metal such as cast iron or oxidizedstainless steel is used, it is preferably coated to provide increasedresistance to erosion by the molten metal flowing about it and to reduceor eliminate the contamination of the molten metal. A suitable coatingwould be a Whiting sodium silicate wash which comprises precipitatedcalcium carbonate in water and contains a small amount of sodiumsilicate as a binder.

Referring now to FIG. 3, the float-distributor 1 of this invention isshown in place in a direct chill cast apparatus prior to the beginningof casting. The direct chill casting apparatus 40 shown thereincomprises a table 41 and a novel direct chill casting mold assembly 42which is the subject of companion patent application Ser. No. 171,461,by LE. Dore and CR. McNutt, filed of even date herewith and assigned tothe assignee of the instant invention.

It is preferred that the float-distributor of this invention be employedwith the novel casting mold assembly 42 which will now be brieflydescribed. The casting mold assembly 42 comprises a mold liner 43 and amold manifold 44. The mold manifold 44 contains at least two chambers 45and 46 separated by an annular web 47 having a plurality of distributionholes 48 substantially equally spaced about it. An inlet, now shown, tothe first chamber 45 is provided for connection with a source of coolingmedium under pressure. A substantial pressure drop is taken across thedistribution holes 48.

The cooling medium is siphoned from the second chamber 46 via aplurality of siphon ports 49 disposed about the internal periphery ofthe mold manifold 44 and a siphon leg 50 defined by the space betweenthe mold manifold 44 and mold liner 43. The cooling medium is dischargedfrom the siphon leg 50 at an annular discharge slot 51.

This novel direct chill casting mold assembly 42 provides a highlyuniform distribution pattern of cooling medium about the periphery ofthe mold over a wide range of cooling medium flow rates.

The direct chill casting apparatus 40 of FIG. 3 also includes a launder52 or trough which communicates preferably with a source of moltenaluminum or aluminum base alloy. The molten aluminum is discharge fromthe trough 52 and fed to the mold via a feed nozzle 5.

A cover plate 53 is employed covering the top of the mold liner 43having hole 54 for the passage of the feed nozzle therethrough and holes55 for the passage of the connecting arms 18 of the float-distributor lof this invention.

Pal nuts 56 or like means are secured to the connecting arms 18 at apoint where they have passed through the holes 55 in the cover plate 53.These nuts 56 provide flanges which support the float-distributor 1prior to the beginning of casting. A bottom block 57 is employed priorto the beginning of casting in order to form a bottom for the castingmold until the cast metal is sufflciently solidified to begin a drop.

in practice, the molten aluminum from the trough 52 would pass throughthe feed nozzle and about the distributor cone D and be collected withinthe space defined by the mold liner 43 and bottom block 57. After themolten aluminum is sufflciently solidified, the casting is withdrawnfrom the mold liner 43 by the descent of the bottom block 57.

FIG. 4 shows the same apparatus 40 as in FIG. 3 during an actual castingdrop. As shown therein, the level of molten aluminum within the mold 43has risen to a point where the float-distributor is now in floatingengagement with the molten aluminum and is no longer supported by theflanges 55 resting against the cover plate 53.

FIG. 4 shows that the molten aluminum level is such that only a smallportion of the inclined surface 13 which forms the means for increasingthe bouyancy of the float 2 is submerged. The degree of submergence ofthe float 2 is dependent on the flow rate of molten metal flowing aboutthe distributor cone D. At higher flow rates, the degree of float 2submergence is greater and the bouyancy of the float is correspondinglyincreased by virtue of the unique inclined surface, thereby allowing thefloat-distributor l to operate effectively even at relatively highmolten metal flow rates.

In operation, the float-distributor l of this invention regulates theflow of metal issuing from the feed nozzle 5 in correspondence with thelevel of the molten metal in the mold 43. As the level of the moltenmetal in the mold 43 increases, the cone D protrudes further into thefeed nozzle 5, thereby reducing the molten metal flowing issuing fromthe feed nozzle. If the height of the metal in the mold 43 becomessufflciently high, the cone distributor D will completely shut off metalflow from the feed nozzle 5.

As the height of the molten metal in the mold 43 de creases, the conedistributor D protrudes less within the feed nozzle 5 or is completelydisplaced from the end of the feed nozzle, thereby permitting increasedflow rates of metal to issue from the feed nozzle.

Therefore, the float-distributor l of this invention provides a highlyeffective means for closely regulating the level of molten metal in themold 43 and is highly effective and stable even at relatively high metalflow rates issuing from the feed nozzle 5.

While the means for connecting the distributor cone to the float hasbeen described with reference to the use of arms, other connecting meansas are well known in the art could be employed; however, the use of armsis preferred because they provide maximum mechanical stability combinedwith small size to provide substantially uniform molten metaldistribution around the periphery of the mold.

It is to be understood that the invention is not limited to theillustrations described and shown herein, which are deemed to be merelyillustrative of the best modes of carrying out the invention, and whichare suitable of modification of form, size, arrangement of parts anddetails of operation. The invention rather is intended to encompass allsuch modifications which are within its spirit and scope as defined bythe claims.

What is claimed is:

l. A float-distributor for distributing molten metal and controlling itsheight in a direct chill casting mold, said molten metal issuing from afeed nozzle associated with said mold, said float-distributorcomprising:

float means adapted to float substantially on the surface of said moltenmetal in said mold, said float means being further adapted to fit aboutsaid feed nozzle; said float means including means for increasing thebouyancy of said float means as the flow of molten metal issuing fromsaid feed nozzle increases; and

means supported by said float means for distributing said molten metalabout the periphery of said mold and controlling the level of saidmolten metal in said mold.

2. A float-distributor as in claim 1 wherein said float means comprisesa member having top and bottom portions and heaving a hole passingsubstantially centrally therethrough, said feed nozzle passing throughsaid hole in said float means and wherein said bouyancy increasing meanscomprises an outwardly extending inclined portion between said top andbottom portions of said float means extending about the periphery ofsaid float means.

3. A float-distributor as in claim 2 wherein said inclined portionextends over only a portion of the thickness of said float between saidtop and bottom portions and a peripheral wall portion is provided whichcommunicates with said inclined portion and said top portion.

4. A float-distributor as in claim 2 wherein said float means has acylindrical periphery in correspondence to a mold having a cylindricalperiphery and wherein the diameter of said float means is from about0.86 X [.D. inch 0.8] inch to about 0.98 X [.D inch 0.82 inch, where[.D. inch is in the inside diameter of said mold.

5. A float-distributor as in claim 4 wherein the diame ter to thicknessratio of said float means is greater than 3 to l.

6. A float-distributor as in claim 5 wherein said distributing meanscomprises a cone shaped distributor adapted to be supported below saidfeed nozzle, said cone shaped distributor being adapted to besubstantially centered about the longitudinal axis of said feed nozzle,said cone shaped distributor having an apex angle of from about 60 toabout 7. A float-distributor as in claim 6 wherein the apex of said coneshaped distributor has a substantially spherical shape, therebypermitting misalignment between the cone axis and the feed nozzlelongitudinal axis of up to about 3.

8. A float-distributor as in claim 7 wherein the hole in said floatmeans has a first portion having a diameter slightly larger than theoutside diameter of said feed nozzle and a second portion communicatingwith said molten metal having a diameter substantially larger than saidfeed nozzle; whereby said first portion of said hole provides the meansfor maintaining the position of said cone shaped distributor relative tothe longitudinal axis of said feed nozzle and said second portion ofsaid hole provides means for preventing capillary flow of said moltenmetal between said feed nozzle and said float.

9. A float-distributor as in claim 8 wherein the ratio of the basediameter of said cone shaped distributor to the diameter of the bore ofsaid feed nozzle is from about 1.6 to 1 to 2 to 1.

10. A float-distributor as in claim 9 wherein said cone shapeddistributor is formed of a material having a density greater than orequal to aluminum.

11. A float-distributor as in claim 10 wherein said cone shapeddistributor is supported by said float by means of a pair of narrowconnecting arms which are integrally formed as part of said cone shapeddistributor whereby a substantially uniform distribution of molten metalis obtained about the periphery of said mold.

12. A float-distributor as in claim 7 wherein said float means is formedof Marinite and said cone shaped distributor is formed of heat resistantcast iron.

13. A float distributor for distributing molten metal and controllingits height in a direct chill casting mold, said molten metal issuingfrom a feed nozzle associated with said mold, said float-distributorcomprising:

float means adapted to float substantially on the surface of said moltenmetal in said mold, said float means having a hole substantiallycentrally therethrough, said feed nozzle passing through said hole andsaid float means and extending below said float means;

means communicating with said float means for preventing flow of moltenmetal by capillary action between said float means and said feed nozzle;and means supported by said float means for distributing said moltenmetal about the peripheryof said mold; said hole in said float meansbeing adapted to maintain accurate alignment between said distributingmeans and said feed nozzle.

14. A float-distributor as in claim 13 wherein said means for preventingcapillary flow of molten metal between said float means and said feednozzle comprises an anti-capillary peripheral slot between said feednozzle and said hole in said float means, said peripheral slot beingformed by dividing said hole into at least two portions, a first portionhaving a diameter slightly larger than the outside diameter of said feednozzle and a second portion communicating with said molten metal in saidmold having a diameter substantially larger than said feed nozzle,whereby said first'portion of said hole provides means for maintainingthe accurate alignment between said distributing means and said feednozzle and said second portion defines with said feed nozzle saidanti-capillary slot.

, 15. A float-distributor as in claim 14 wherein said distributing meanscomprises a cone shaped distributor adapted to be supported below saidfeed nozzle, said cone shaped distributor being adapted to besubstantially centered about the longitudinal axis of said feed nozzle,said cone shaped distributor having an apex angle of from about 60 toabout l50.

16. A float-distributor as in claim [5 wherein the apex of said coneshaped distributor has a substantially spherical shape therebypermitting misalignment between the cone axis and the feed nozzlelongitudinal axis of up to about 3.

17. A float-distributor as in claim 16 wherein the ratio of the basediameter of said cone shaped distributor to the diameter of the bore ofsaid feed nozzle is from about 1.6 to 1 to 2 to l.

18. A float-distributor as in claim 17 wherein said cone shapeddistributor is formed of a material having a density greater than orequal to aluminum.

19. A float-distributor as in claim 18 wherein said cone shapeddistributor is supported by said float by means of a pair of narrowconnecting arms which are integrally formed as part of said cone shapeddistributor whereby a substantially uniform distribution of molten metalis obtained about the periphery of said mold.

20. A float-distributor as in claim 19 wherein said float meanscomprises a member having top and bottom portions and having aperipheral wall portion communicating with at least one of said top andbottom portions.

21. A float-distributor as in claim 20 wherein said peripheral wallportion has a cylindrical shape in correspondence to a mold having acylindrical periphery and wherein the diameter of said float means isfrom about 0.86 X [.D. inch 0.81 inch to about 0.98 X LD. inch 0.82 inchwhere I.D. inch is the inside diameter of said mold.

22. A float-distributor as in claim 21 wherein the diameter to thicknessratio of said float means is greater than 3 to l.

23. A float-distributor for distributing molten metal and controllingits height in a direct chill casting mold, said molten metal issuingfrom a feed nozzle associated with said mold, said float-distributorcomprising:

float means for floating substantially on the surface of said moltenmetal in said mold, said float means being adapted to fit about saidfeed nozzle; and distribution means supported below said float means,

said distribution means being adapted to be supported below said feednozzle and comprising a cone shaped distributor having an apex angle offrom about 60 to about the apex of said cone shaped distributor beingrounded off into a sub stantially spherical surface, said cone shapeddistributor being adapted to be substantially centered about thelongitudinal axis of said feed nozzle, said cone shaped distributorbeing formed of a material having a density greater than or equal toaluminum.

24. A float-distributor as in claim 23 wherein the ratio of the basediameter of said cone shaped distributor to the diameter of the bore ofsaid feed nozzle is from about 1.6 to l to 2 to 1.

252A float-distributor as in claim 24 wherein said float means comprisestop and bottom portions and a peripheral wall portion communicating withat least spondence to a mold having a cylindrical periphery and whereinthe diameter of said float means is from about 0.86 X [.D. inch 0.81inch to about 0.98 X l.D. inch 0.82 inch, where [.D. inch is the insidediameter of the mold.

27. A float-distributor as in claim 26 wherein said float means isformed of Marinite and said cone shaped distributor is formed of heatresistant cast iron.

28. in an apparatus as in claim 24, the improvement wherein said coneshaped distributor is supported by said float by means of a pair ofnarrow connecting arms which are integrally formed as part of said coneshaped distributor whereby a substantially uniform distribution ofmolten metal is obtained about the periphery of said mold.

29. Inan apparatus as in claim 28, the improvement wherein said floatmeans comprises a member having top and bottom portions and having ahole passing substantially centrally therethrough, said feed nozzlepassing through said hole.

30. In an apparatus as in claim 29, the improvement wherein the hole insaid float means has a first portion having a diameter slight largerthan the outside diameter of said feed nozzle and a second portioncommunicating with said molten metal in said mold having a diametersubstantially larger than said feed nozzle; whereby said first portionof said hole provides the means for maintaining the position of saidcone shaped distributor relative to the longitudinal axis of said feednozzle and said second portion of said hole provides means forpreventing capillary flow of molten metal between said feed nozzle andsaid float.

31. In an apparatus as in claim 30, the improvement wherein said floatmeans further includes means for increasing the buoyancy of said floatas the flow of molten metal issuing from said feed nozzle increases.

32. In an apparatus as in claim 31, the improvement wherein saidbuoyancy increasing means comprises an outwardly extending inclinedportion between said top and bottom portions of said float meansextending about the periphery of said float means and communicating withsaid bottom portion of said float means.

1. A float-distributor for distributing molten metal and controlling itsheight in a direct chill casting mold, said molten metal issuing from afeed nozzle associated with said mold, said float-distributorcomprising: float means adapted to float substantially on the surface ofsaid molten metal in said mold, said float means being further adaptedto fit about said feed nozzle; said float means including means forincreasing the bouyancy of said float means as the flow of molten metalissuing from said feed nozzle increases; and means supported by saidfloat means for distributing said molten metal about the periphery ofsaid mold and controlling the level of said molten metal in said mold.2. A float-distributor as in claim 1 wherein said float means comprisesa member having top and bottom portions and heaving a hole passingsubstantially centrally therethrough, said feed nozzle passing throughsaid hole in said float means and wherein said bouyancy increasing meanscomprises an outwardly extending inclined portion between said top andbottom portions of said float means extending about the periphery ofsaid float means.
 3. A float-distributor as in claim 2 wherein saidinclined portion extends over only a portion of the thickness of saidfloat between said top and bottom portions and a peripheral wall portionis provided which communicates with said inclined portion and said topportion.
 4. A float-distributor as in claim 2 wherein said float meanshas a cylindrical periphery in correspondence to a mold having acylindrical periphery and wherein the diameter of said float means isfrom about 0.86 X I.D. inch - 0.81 inch to about 0.98 X I.D inch - 0.82inch, where I.D. inch is in the inside diameter of said mold.
 5. Afloat-distributor as in claim 4 wherein the diameter to thickness ratioof said float means is greater than 3 to
 1. 6. A float-distributor as inclaim 5 wherein said distributing means comprises a cone shapeddistributor adapted to be supported below said feed nozzle, said coneshaped distributor being adapted to be substantially centered about thelongitudinal axis of said feed nozzle, said cone shaped distributorhaving an apex angle of from about 60* to about 150*.
 7. Afloat-distributor as in claim 6 wherein the apex of said cone shapeddistributor has a substantially spherical shape, thereby permittingmisalignment between the cone axis and the feed nozzle longitudinal axisof up to about 3*.
 8. A float-distributor as in claim 7 wherein the holein said float means has a first portion having a diameter slightlylarger than the outside diameter of said feed nozzle and a secondportion communicating with said molten metal having a diametersubstantially larger than said feed nozzle; whereby said first portionof said hole provides the means for maintaining the position of saidcone shaped distributor relative to the longitudinal axis of said feednozzle and said second portion of said hole provides means forpreventing capillary flow of said molten metal between said feed nozzleand said float.
 9. A float-distributor as in claim 8 wherein the ratioof the base diameter of said cone shaped distributor to the diameter ofthe bore of said feed nozzle is from about 1.6 to 1 to 2 to
 1. 10. Afloat-distributor as in claim 9 wherein said cone shaped distributor isformed of a material having a density greater than or equal to aluminum.11. A float-distributor as in claim 10 wherein said cone shapeddistributor is supported by said float by means of a pair of narrowconnecting arms which are integrally formed as part of said cone shapeddistributor whereby a substantially uniform distribution of molten metalis obtained about the periphery of said mold.
 12. A float-distributor asin claim 7 wherein said float means is formed of Marinite and said coneshaped distributor is formed of heat resistant cast iron.
 13. A floatdistributor for distributing molten metal and controlling its height ina direct chill casting mold, said molten metal issuing from a feednozzle associated with said mold, said float-distributor comprising:float means adapted to float substantially on the surface of said moltenmetal in said mold, said float means having a hole substantiallycentrally therethrough, said feed nozzle passing through said hole andsaid float means and extending below said float means; meanscommunicating with said float means for preventing flow of molten metalby capillary action between said float means and said feed nozzle; andmeans supported by said float means for distributing said molten metalabout the periphery of said mold; said hole in said float means beingadapted to maintain accurate alignment between said distributing meansand said feed nozzle.
 14. A float-distributor as in claim 13 whereinsaid means for preventing capillary flow of molten metal between saidfloat means and said feed nozzle comprises an anti-capillary peripheralslot between said feed nozzle and said hole in said float means, saidperipheral slot being formed by dividing said hole into at least twoportions, a first portion having a diameter slightly larger than theoutside diameter of said feed nozzle and a second portion communicatingwith said molten metal in said mold having a diameter substantiallylarger than said feed nozzle, whereby said first portion of said holeprovides means for maintaining the accurate alignment between saiddistributing means and said feed nozzle and said second portion defineswith said feed nozzle said anti-capillary slot.
 15. A float-distributoras in claim 14 wherein said distributing means comprises a cone shapeddistributor adapted to be supported below saId feed nozzle, said coneshaped distributor being adapted to be substantially centered about thelongitudinal axis of said feed nozzle, said cone shaped distributorhaving an apex angle of from about 60* to about 150*.
 16. Afloat-distributor as in claim 15 wherein the apex of said cone shapeddistributor has a substantially spherical shape thereby permittingmisalignment between the cone axis and the feed nozzle longitudinal axisof up to about 3*.
 17. A float-distributor as in claim 16 wherein theratio of the base diameter of said cone shaped distributor to thediameter of the bore of said feed nozzle is from about 1.6 to 1 to 2to
 1. 18. A float-distributor as in claim 17 wherein said cone shapeddistributor is formed of a material having a density greater than orequal to aluminum.
 19. A float-distributor as in claim 18 wherein saidcone shaped distributor is supported by said float by means of a pair ofnarrow connecting arms which are integrally formed as part of said coneshaped distributor whereby a substantially uniform distribution ofmolten metal is obtained about the periphery of said mold.
 20. Afloat-distributor as in claim 19 wherein said float means comprises amember having top and bottom portions and having a peripheral wallportion communicating with at least one of said top and bottom portions.21. A float-distributor as in claim 20 wherein said peripheral wallportion has a cylindrical shape in correspondence to a mold having acylindrical periphery and wherein the diameter of said float means isfrom about 0.86 X I.D. inch - 0.81 inch to about 0.98 X I.D. inch - 0.82inch where I.D. inch is the inside diameter of said mold.
 22. Afloat-distributor as in claim 21 wherein the diameter to thickness ratioof said float means is greater than 3 to
 1. 23. A float-distributor fordistributing molten metal and controlling its height in a direct chillcasting mold, said molten metal issuing from a feed nozzle associatedwith said mold, said float-distributor comprising: float means forfloating substantially on the surface of said molten metal in said mold,said float means being adapted to fit about said feed nozzle; anddistribution means supported below said float means, said distributionmeans being adapted to be supported below said feed nozzle andcomprising a cone shaped distributor having an apex angle of from about60* to about 150*, the apex of said cone shaped distributor beingrounded off into a substantially spherical surface, said cone shapeddistributor being adapted to be substantially centered about thelongitudinal axis of said feed nozzle, said cone shaped distributorbeing formed of a material having a density greater than or equal toaluminum.
 24. A float-distributor as in claim 23 wherein the ratio ofthe base diameter of said cone shaped distributor to the diameter of thebore of said feed nozzle is from about 1.6 to 1 to 2 to
 1. 25. Afloat-distributor as in claim 24 wherein said float means comprises topand bottom portions and a peripheral wall portion communicating with atleast one of said top and bottom portions, said bottom portioncommunicating with said molten metal in said mold.
 26. Afloat-distributor as in claim 25 wherein said peripheral wall portionhas a cylindrical shape in correspondence to a mold having a cylindricalperiphery and wherein the diameter of said float means is from about0.86 X I.D. inch - 0.81 inch to about 0.98 X I.D. inch - 0.82 inch,where I.D. inch is the inside diameter of the mold.
 27. Afloat-distributor as in claim 26 wherein said float means is formed ofMarinite and said cone shaped distributor is formed of heat resistantcast iron.
 28. In an apparatus as in claim 24, the improvement whereinsaid cone shaped distributor is supported by said float by means of apair of narrow connecting arms which are integrally formed as part ofsaid cone shaped distributor whereby a substantially uniformdistribution of molten metal is obtained about the periphery of saidmold.
 29. In an apparatus as in claim 28, the improvement wherein saidfloat means comprises a member having top and bottom portions and havinga hole passing substantially centrally therethrough, said feed nozzlepassing through said hole.
 30. In an apparatus as in claim 29, theimprovement wherein the hole in said float means has a first portionhaving a diameter slight larger than the outside diameter of said feednozzle and a second portion communicating with said molten metal in saidmold having a diameter substantially larger than said feed nozzle;whereby said first portion of said hole provides the means formaintaining the position of said cone shaped distributor relative to thelongitudinal axis of said feed nozzle and said second portion of saidhole provides means for preventing capillary flow of molten metalbetween said feed nozzle and said float.
 31. In an apparatus as in claim30, the improvement wherein said float means further includes means forincreasing the buoyancy of said float as the flow of molten metalissuing from said feed nozzle increases.
 32. In an apparatus as in claim31, the improvement wherein said buoyancy increasing means comprises anoutwardly extending inclined portion between said top and bottomportions of said float means extending about the periphery of said floatmeans and communicating with said bottom portion of said float means.